The invention relates to a sewing machine and more particularly relates to a loop catching device for a sewing machine, which is to improve a loop taking condition of the loop taker. For attaining this object, the invention comprises substantially an electromagnetic element operated by pattern control data stored in a memory in synchronism with the vertical movement of the needle, and a loop catching member having a looper operated by the electromagnetic element in synchronism with the movement of the needle to catch the upper thread loop and hold the same for a predetermined time until the loop is taken by the hook of the loop taker.
In a zigzag sewing machine, it is generally known that the crossing conditions of the vertically reciprocating needle and the rotating hook of the loop taker are different at the needle dropping positions, for example, between the most rightward position and the most leftward position of the permissible needle swinging range. It is also known that the loop is often skipped by the hook of the looptaker at one of the two needle positions because the crossing condition of the needle and the hook is unsuited at that needle portion.
So far, various countermeasures have been provided to eliminate such a loop skipping phenomenon. For example, a method is known how to mechanically synchronize the movements of the needle and the loop taker at each crossing point. Another known method teaches how to electrically drive the loop taker in synchronism with the movement of the needle. Such methods, however, have been found unsatisfactory because they fail to prevent the skip of a loop by the loop taker. Especially the latter method requires a comparatively much power, and accordingly a device of large size will result which is difficult to be installed in a limited space of the sewing machine housing.